[PATCH] RTC class: error checks

The rtc_is_valid_tm() routine needs to treat some of the fields it checks as
unsigned, to prevent wrongly accepting invalid rtc_time structs; this is the
same approach used elsewhere in the RTC code for such tests.

Conversely, rtc_proc_show() is missing one invalid-day-of-month test that
rtc_is_valid_tm() makes: there is no day zero.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/rtc/rtc-proc.c b/drivers/rtc/rtc-proc.c
index 1b2c2ca..2943d83 100644
--- a/drivers/rtc/rtc-proc.c
+++ b/drivers/rtc/rtc-proc.c
@@ -61,7 +61,7 @@
 			seq_printf(seq, "%02d-", alrm.time.tm_mon + 1);
 		else
 			seq_printf(seq, "**-");
-		if ((unsigned int)alrm.time.tm_mday <= 31)
+		if (alrm.time.tm_mday && (unsigned int)alrm.time.tm_mday <= 31)
 			seq_printf(seq, "%02d\n", alrm.time.tm_mday);
 		else
 			seq_printf(seq, "**\n");